Synthesis and Structural Aspects of Two Trinuclear Cyano-bridged Heterometallic Complexes with Monodentate Coordination of Perchlorate and Acetate Anions

Abstract

Two new cyano-bridged trinuclear heterometallic complexes [Ca2(phen)4(ClO4)(H2O)3- Fe(CN)6]・H2O (1) and [Ca2 (phen)4(CH3COO)(H2O)3Fe(CN)6]・2H2O (2) (where phen = 1,10- phenanthroline) have been synthesized and characterized by single-crystal X-ray diffraction techniques, IR spectroscopy and thermogravimetric analysis. The structure of complex 1 features a central [Fe(CN)6]3− unit that links a monocation [Ca(phen)2(H2O)(ClO4)]+ and a dication [Ca(phen)2- (H2O)2]2+ via two trans cyanide bridges. Similarly, complex 2 also features a central [Fe(CN)6]3− unit that links a monocation [Ca(phen)2(H2O)(CH3COO)]+ and a dication [Ca(phen)2(H2O)2]2+ via two trans cyanide bridges. In 1 and 2, both Ca centers are seven-coordinated and achieve a pentagonal- bipyramidal geometry whereas the Fe center in both the complexes possesses a distorted octahedral geometry. Intra- and intermolecular hydrogen bonding networks are present in 1 and 2 that impart the overall molecular stability to both the systems.